This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The USC component of the CNTN is designed to identify, recruit, enroll, and assess a cohort of 70 AIDS patients with life expectancies of less than one year of whom about 12 will be autopsied each year. Tissue samples will be obtained from 12-15 control cases dying after non-neurologic trauma will be sent to the tissue repository bank over 5 years. The principal investigator and a neurologist will perform the clinical procedures required of the project and oversee a research assistant who will perform the neuropsychocologic assessments. A neuropathologist and pathology assistant (deanor) will conduct the neurologic autopsy and assist in the performance of the general autopsy when permitted by the family. The USC investigators will transmit data and specimens to the CNTN Administrative and Data Center and Brain Bank at USCD, which will provide data management, tissue storage, coordination among network sites, and quality control of all aspects of the project through training and monitoring. Recruitment of participants will will be focused at the LAC+USC Rand Schrader HIV?AIDS Clinic which follows an estimated 2,650 AIDS Patients. Research Subjects will be replaced as they die or are lost to follow up. These patients will undergo structured Medical, neurologic, neuropsychologic, immunocologic, and virologic assessments every six months until they die. Postmortem will be conducted at the LA County Hospital if the subject dies within that facility or they will be transferred to the Norris Cancer Research Hospital. All post mortem examinations will be conducted within 12 hours of death.